It is commonplace in the data processing art for software to be written in a modular structure. The tasks which the software performs are typically embodied in a set of subtasks which, depending on the development environment, may be referred to as procedures, functions, methods, subroutines or events. An event is a particular software routine that receives user interactions via standard user interface devices. Although, again depending on the development system, these may have different connotations, for the purposes of the present invention they will be collectively referred to as routines.
A complex software program which may be typical of the complex tasks performed by modern data processing systems may include a multitude of such procedures. Moreover, routines typically refer to other routines, whereby a hierarchical structure results. In a sophisticated software product, a complex hierarchical, or nested, chain of routine references may result. Tracking this hierarchical chain of dependencies as a development of a software program progresses, may be difficult. Additionally, maintenance of the product, which may be performed by persons other than the developers, may also be complicated by the complex hierarchical structure. Thus, there is a need in the art for a mechanism to track and display the cross referencing of procedures in data processing software, thereby allowing the programmer to have knowledge of the calling and called routines that will be affected if changes are applied to any given routine.